comparison of restoetion of different restortion te hniques.pptx

comparison of restoetion

1. Comparison Of Different Restoration Techniques For Endodontically Treated Teeth Guided by: Presented By: Dr Bobbin Gill Dr Ritu Khichar Dr Nirmala Bishnoi Dr vaishak Augustine

2. Introduction One of the primary reasons for the extraction of endodontically treated teeth (ETT) is the formation of nonrestorable fractures in the coronal parts of the teeth. This is attributed to the difference in the biomechanical properties between ETT and vital teeth .

3. In this respect, coronal restoration of ETT has great importance in increasing the survival rate of these teeth. Posterior resin composites have become preferred materials in coronal restorations because of their sufficient features such as applicable in a single session and having satisfactory aesthetic and mechanical properties

4. Bulk-fill composites, which can be applied and polymerised in a single layer of 4-5 mm thickness, are separated from conventional composites with their increased depth of cure properties . With these features, bulk-fill composites reduce the negative aspects of polymerisation such as polymerisation shrinkage and shrinkage stresses more successfully than conventional composites .

5. Therefore, bulk-fill composites are recommended to be used in deep and narrow cavities deeper than 4 mm, such as postendodontic restorations, instead of conventional composite.

6. Restoration strengthening with fibres can be done by various methods. One of them is using shortened fibre-reinforced composite (SFRC) . It has been reported that shortened fibres in the SFRC prevent the crack or fracture from moving along the tooth and act as a load barrier against high occlusal forces.

7. Another method of strengthening restorations with utilizing fibres is the use of woven fibres . Research studies showed that it is benefited to support the restorations with woven fibres , especially in ETT with excessive substance loss. It has been reported that the problems such as microleakage , postoperative sensitivity, secondary caries, and the difficulties in providing ideal contact and contour in teeth with extensive substance loss can be reduced by applying indirect restorations that can be polymerised , finished, and polished outside the mouth, and successful results can be obtained.

8. C linical success of a restorative application is directly related to the physical and mechanical properties of the material used. null hypothesis of this study is that there will be no significant difference between the 5 techniques examined.

9. Materials and Methods Sample Preparation for Fracture Strength Analysis One hundred and forty caries-free, third molars were divided into 7 groups , consisting of 5 restoration groups using different restoration techniques, a negative control (including teeth that were endodontically treated but were not restored), and a positive control (no treatment was applied). MOD cavities were prepared.

10. While proceeding to the restoration phase, following the application of 35% orthophosphoric acid to the teeth in all restoration groups, the single-bottle adhesive system (G- aenial Bond, GC Corp., Tokyo, Japan) was applied and polymerised with the LED light-curing device according to the manufacturer instructions. . cavities were then restored as follows:

11. Following endodontic access cavity preparation, all teeth were instrumented using ProTaper rotary file. During preparation, the root canals were irrigated with 2 ml of 2.5% sodium hypochlorite between each file. After completing the instrumentation, 5 ml of 5% EDTA, 5 ml of 2.5% NaOCl , and distilled water were used for the final irrigation, and all teeth were obturated with gutta-percha and AH Plus sealer using the single-cone technique.

12. Group 1 (DC): initially, the missing proximal wall was restored with 1 mm-thick nanohybrid resin composite (G- aenial Posterior, GC Corp., Tokyo, Japan) using the Adapt SuperCap matrix system (Kerr, KerrHawe , Bioggio , Switzerland). After the proximal wall was formed, the matrix was removed, and the rest of the cavity was restored using the same composite, with the incremental technique as 2 mm-thick layers.

13. Group 2 (GWF): after creating the proximal wall as described in group 1, a thin layer of flowable resin composite (FRC) (G- aenial Universal Flo, GC Corp., Tokyo, Japan) was applied into the cavity. Afterwards, a piece of glass woven fibre (GWF) ( Everstick NET, GC Corp., Tokyo, Japan) with 8 mm length and 3 mm width was cut and placed in this composite, and the first fibre piece was placed in a buccolingual direction to be in close contact with the buccal and lingual walls and was cured for 20 s. After applying a thin layer of FRC again, the second piece of GWF was placed on the uncured FRC perpendicular to the first piece, covering the mesial and distal walls, and was cured for 20 s. rest of the cavity was restored with nanohybrid composite resin again with the incremental technique.

14. Group 3 (SFRC): after creating the proximal wall as described in group 1, shortened fibre-reinforced resin composite (SFRC) ( EverX Posterior, GC Corp., Tokyo, Japan) was applied to the cavity with 4 mm thickness. . remaining 2 mm deep part of the cavity was restored using nanohybrid composite resin (G- aenial Posterior, GC Corp., Tokyo, Japan)

15. Group 4 (FBFC): after the etching and adhesive procedures, the ring matrix system Adapt SuperCap (Kerr, KerrHawe , Bioggio , Switzerland) was placed. Unlike other groups, 4 mm-thick SDR bulk-fill ( Dentsply , Konstanz, Germany) was applied to the entire cavity at one time, without forming proximal wall, and was polymerised with light. remaining occlusal 2 mm part of the cavity was restored with nanohybrid composite resin G- aenial Posterior.

16. Group 5 (IC): first of all, cavity impression was taken with Vinyl Polyether Silicone impression material in this group. After preparing working models from hard plaster, indirect restorations were formed using indirect composite resin . Formed restorations were polymerised in an indirect composite curing oven (GC Labolight LV-III, GC Corp., Tokyo, Japan) for 10 minutes. Finally, the restorations were cemented to the cavities using an adhesive cement

17. Fracture Resistance Test After the endodontic and restorative procedures were completed, teeth in all groups, including the control groups, were embedded into autopolymerising polymethyl methacrylate, up to 1 mm apical of the cementoenamel junction, using cylindrical moulds . All samples were kept in distilled water at room temperature for one week until the fracture test. Finally, the specimens were placed in a universal testing machine

18. fractured specimens were then removed from acrylic resin and assessed for fracture patterns. Repairable fractures above the level of the simulated bone were defined as “favorable failures,” whereas unrepairable fractures below this line were defined as “ unfavourable failures.

19. Sample Preparation for Flexure Strength and Modulus of Elasticity Tests Group 1: the Mylar strip tape was placed on the bottom of the 2 × 2 × 25 mm-sized mould placed on a slide. A nanohybrid composite was placed in the mould and slightly pressed by placing another strip, and slide on it again. polymerisation was achieved by applying 20 seconds of light from three points of the slide each, two edges, and the middle part of the mould . . the slide was removed, and 20 seconds of light was applied to the same areas again. Therefore, the total polymerisation time was increased to 120 seconds

20. Group 2: flowable composite was applied to the mould prepared as described in group 1, but it was not polymerised since the GWF was cut to size 24 × 2 mm and placed in the bottom of the mould . nanohybrid resin was applied into the mould , and the application was completed as described in group 1

21. Group 3: application steps described in group 1 were applied in the same way, but SFRC was used instead of the conventional nanohybrid composite. Group 4: application steps described in group 1 were applied in the same way, but a bulk-fill resin composite (SDR, Dentsply , Konstanz, Germany) was used instead of the conventional nanohybrid composite.

22. Group 5: indirect composite resin samples were placed as described in the previous groups, and their initial polymerisation was completed. Subsequently, samples were placed in an indirect composite curing oven for 10 minutes in order to ensure final polymerization.

23. All samples were placed in distilled water at 37° C for 24 hours before subjected to a three-point bending test. maximum force values causing the fracture were determined .

24. Statistical Analysis: Statistical analysis of the study was done with the SPSS package program (IBM Statistics, Illinois, USA), and definitive statistics were obtained for all data. Group comparisons were made with oneway ANOVA, and binary comparisons between groups were evaluated by the post hoc Tukey HSD test. For all tests, p = 0.05 value was considered significant.

25. Fracture Strength and Failure Mode Results Among the restoration groups, the highest fracture resistance was observed in the SFRC group. no significant difference was observed between bulkfill and direct composite restoration groups. lowest fracture resistance was observed in the GWF group. However, no significant difference was found among GWF, IC, and DC groups. an 85% reduction was found in the fracture resistance of the negative control group, compared to positive control group.

26. This decrease was found to be at the level of 38% in the GWF group, 30% in the indirect composite group, 28% in the direct composite group, 25% in the bulk-fill group, and 18% in the SFRC group a total of 36 samples from 100 samples tested in restoration groups were classified as favorable, and 64 samples were classified as unfavorable.

27. Flexural Strength and Modulus of Elasticity Results The highest flexural strength was observed in the SFRC group . flexural strength values observed in the SFRC group were found to be significantly higher than those of the direct and indirect composite groups (p < 0.05), despite no significant difference was found between the SFRC and FBFC groups (p = 0.737). While the lowest flexural strength values were observed in the GWF group, no statistically significant difference was found between GWF and direct (p = 0.775) and indirect (p = 0.733) composite groups

28. In terms of the modulus of elasticity, the SFRC group was found to be significantly higher compared to other groups (p < 0.05). lowest modulus of elasticity was observed in the FBFC group, but the difference between this group and the indirect composite group was not significant (p = 0.61)

29. Discussion Belli et al. stated that MOD cavity preparation caused a decrease in fracture strength. Reeh et al. reported that the fracture resistance of ETT with an occlusal cavity was decreased only by 5%, and when the MOD cavity was prepared, the fracture strength decreased by 69%. Similar to the mentioned studies, in this study, it was determined that there was an 85% reduction in the fracture strength of the teeth with the MOD cavity compared to the teeth that did not prepare.

30. Fracture resistance values in the SFRC group were found to be significantly higher than those in the GWF and indirect composite resin groups. It was found that the difference between the fracture resistance values obtained in the SFRC group and flowable bulk-fill and direct composite groups was not statistically significant.

31. Despite the fibre content, the lowest fracture resistance was observed in the samples in the GWF group. Therefore, the null hypothesis was rejected.

32. In this study, the difference between the indirect and direct composite resin groups in terms of fracture strength values was not significant. In this study, we think that the bulk-fill composite resin, which is used as a base material under the nanohybrid composite, can be a factor in the occurrence of high fracture resistance values by absorbing occlusal pressures.

33. Both Belli et al. and Kemaloglu et al. showed that the polyethylene woven fibre (PWF) placed on the cavity base and walls significantly increases the fracture resistance. opposite result encountered in woven fibre application is due to the fibre types used. Kemaloglu et al. used polyethylene fibre in their studies, while the glass fibre was used in this study.

34. In this study, the percentage of restorable or favourable fractures in composite restorations applied without fibre usage is 10%, while it is 25% in glass fibre -reinforced restorations. researcher claimed that the distribution of the fibre in the resin matrix determines its physical properties.

35. Although the three-dimensional structure of the polyethylene fibre strengthens the polymer bidirectionally , the glass woven fibre enables reinforcement in one direction due to its anisotropic feature. This creates weak areas in fibre -reinforced structures depending on the direction of the fracture forces.

36. Yasa et al. reported that SFRC has better fracture resistance and flexure strength values, as well as shows lower polymerisation shrinkage values against bulk-fill composites. In addition, when the types of fractures were evaluated, it was claimed that the use of fibres preserved the remaining tooth structure and caused more repairable fractures than other groups

37. Low polymerisation shrinkage may reduce the tension occurring in the cavity wall, thereby reducing tubercular deflection and microcracks on the walls. Therefore, durable restorations can be formed for fracture resistance tests. in this study, the highest flexural strength was observed in the SFRC group. lowest values were obtained in the GWF group, the difference between the GWF group and the direct and indirect composite groups was not significant.

38. B ig difference observed between SFRC and GWF in terms of flexural strengths may be related to the distribution of fibres in the composite mass. In the SFRC group, glass fibres are distributed evenly within the composite mass, while fibres are concentrated only at the bottom of the composite in the GWF restoration group.

39. In addition, no significant difference was found between the SFRC group and the bulk-fill composite resin group (p > 0.05). This may be due to the high flexural strength feature of the flowable resin composite material which both bulk-fill composite resin and SFRC have. According to these results, it can be concluded that fractures are observed more frequently in restorations with materials with low flexural strength.

40. Conclusions ( i ) MOD cavity preparation in ETT reduces the fracture strength by 85% (ii) SFRC, which gives the best results in this study, can be used to increase the fracture resistance of ETT (iii) GWF group presented the worst direct restoration opinion in terms of fracture strength and flexural strength (iv) Flexural strength and MOE values of restorative materials play important roles in fracture resistance of restorations